The directing valve is also called as director or pilot valve. The directing valve is generally used to control the operation of a pressure adjusting valve (a pressure adjusting device).
FIG. 1 shows a typical pressure adjusting valve assembly 01 comprising a main valve 02, a directing valve 03 and an actuator 04. Specifically, the main valve 02 is connected into a main fluid line 012. The valve body of the main valve 02 includes an inlet chamber 05 coupled to a fluid source (for example, a gas supply station) by the main fluid line 012 and an outlet chamber 06 coupled to a fluid user (for example, a gas user) by the main fluid line 012. As is well known, the connection and disconnection between the inlet chamber 05 and the outlet chamber 06 may be achieved by a valve seat and a valve plug cooperating with the valve seat. The valve plug is forced to move between a position engaged with the valve seat and a position away from the valve seat by the valve stem coupled to the valve plug. The valve stem of the main valve 02 is connected to an actuating member of the actuator 04 (for example, the actuating member may be a diaphragm or a piston). The actuating member divides the controlling chamber of the actuator 04 into a chamber 07, which is in communication with a first pressure chamber 09 of the directing valve 03, and a chamber 08, which is in communication with a second pressure chamber 011 of the directing valve 03. The first pressure chamber 09 senses the change of the pressure of the outlet chamber 06 (or outlet pressure) of the main valve 02 so as to control the opening degree between the second pressure chamber 011 and a third pressure chamber 010 (for example, the third pressure chamber 010 is in fluid communication with the inlet chamber 05 of the main valve 02), and then the change of the opening degree may cause the change of the pressure of the second pressure chamber 011, thus the pressure exerted on the two ends of the actuating member of the actuator 04 is changed and the displacement of the actuating member may cause the displacement of the valve plug of the main valve 02. In this way, the pressure of the outlet chamber 06 of the main valve 02 is self-adjusted by the directing valve 03 and the actuator 04.
FIG. 2a shows the specific configuration of a known directing valve 03. The directing valve 03 comprises a quick releasing hole 032 and a valve port 033 arranged between a valve port gasket 031 and the valve seat. The valve port gasket 031 is coupled to a diaphragm 034 by a supporting plate 035 and a fastener 036. As shown in the drawings, when the pressure in the first pressure chamber 09 on one side of the diaphragm 034 is decreased, the diaphragm 034 moves upwards so as to force the valve port gasket 031 to move upwards, thus the opening degree between the valve port gasket 031 and the valve port 033 is increased. Since the pressure of the third pressure chamber 010 is generally higher than that of the second pressure chamber 011, the pressure in the third pressure chamber 010 is supplied to the second pressure chamber 011. As a result, the pressure across the actuating member of the actuator 04 is changed, and the actuating member forces the valve plug of the main valve 02 to move so that the opening degree of the main valve 02 is increased, thus the outlet pressure of the main valve is increased. In contrast, when the pressure in the first pressure chamber 09 on one side of the diaphragm 034 is increased, the diaphragm 034 moves downwards so as to force the valve port gasket 031 to move downwards, thus the opening degree between the valve port gasket 031 and the valve port 033 is reduced, and the pressure in the second pressure chamber 011 is decreased. As a result, the pressure across the actuating member of the actuator 04 is changed, and the actuating member forces the valve plug of the main valve 02 to move so that the opening degree of the main valve 02 is reduced, thus the outlet pressure of the main valve is decreased. If the pressure in the first pressure chamber 09 is increased gradually, the valve port gasket 031 abuts against the valve port 033, that is to say, the valve port 033 is closed. Then, the quick releasing hole 032 is opened, and the pressure in the second pressure chamber 011 is quickly discharged to the first pressure chamber 09 through the quick releasing hole 032 since the pressure of the second pressure chamber 011 is higher than that of the first pressure chamber 09.
FIG. 2b shows the specific configuration of another known directing valve 03′. The directing valve 03′ comprises a quick releasing hole 032′ and a valve port 033′ arranged between a valve port gasket 031′ and the valve seat. The valve port gasket 031′ is coupled to a diaphragm 034′ by a supporting plate 035′ and a fastener 036′. As shown in the drawings, when the pressure in the first pressure chamber 09′ on one side of the diaphragm 034′ is decreased, the diaphragm 034′ moves downwards so as to force the valve port gasket 031′ to move downwards, thus the opening degree between the valve port gasket 031′ and the valve port 033′ is increased. Since the pressure of the inlet pressure chamber 010′ is higher than that of the second pressure chamber 011′, the pressure in the third pressure chamber 010′ is supplied to the second pressure chamber 011′. As a result, the pressure across the actuating member of the actuator 04 is changed, and the actuating member forces the valve plug of the main valve 02 to move so that the opening degree of the main valve 02 is increased, thus the outlet pressure of the main valve is increased. In contrast, when the pressure in the first pressure chamber 09′ on one side of the diaphragm 034′ is increased, the diaphragm 034′ moves upwards so as to force the valve port gasket 031′ to move upwards, thus the opening degree between the valve port gasket 031′ and the valve port 033′ is reduced, and the pressure in the second pressure chamber 011′ is decreased. As a result, the pressure across the actuating member of the actuator 04 is changed, and the actuating member forces the valve plug of the main valve 02 to move so that the opening degree of the main valve 02 is reduced, thus the outlet pressure of the main valve is decreased. If the pressure in the first pressure chamber 09′ is increased gradually, the valve port gasket 031′ abuts against the valve port 033′, that is to say, the valve port 033′ is closed. Then, the quick releasing hole 032′ is opened, and the pressure in the second pressure chamber 011′ is quickly discharged to the first pressure chamber 09′ through the quick releasing hole 032′ since the pressure of the second pressure chamber 011′ is higher than that of the first pressure chamber 09′.
However, the directing valves as shown in FIGS. 2a and 2b have some problems. That is, the valve port gasket 031 and 031′ need to be coupled to the diaphragm 034, 034′, thus additional elements 035, 036 are needed, thereby increasing the complexity of the installation and the replacement of the elements. In addition, in the known directing valves, the quick releasing hole is arranged on one side away from the valve port gasket.